---
id:
aliases: []
tags:
  - destiny/permanent
  - occupational
  - status/incomplete
  - type/guide
  - authorship/original
title: Wiring Method Selection
---
# Wiring Method Selection

Determine where each wiring method can be used.

NM/SER < PVC < MC < EMT-SS < EMT-Comp < IMC

Below is an example Wiring Method Selection
for a [[ibc-construction-types#5-Over-1 Construction|podium]] construction.

> [!example]
> Wire Material:
> * Less than 100A: CU
> * 100A and larger: AL
>
> Outdoors:
> * Above-ground: EMT-Comp
> * Underground: PVC w/ Rigid Elbows
> 
> Levels 1-2 (Type IA):
> * Concealed: MC
> * Exposed to Structure:
>     * Up to 2"C: PVC In-Slab
>     * 2-1/2"C and larger: EMT-SS OH
> 
> Levels 3-5 (Type IIIA):
> * Concealed: NM/SER
> * Exposed to Structure: PVC OH

<!--
This needs reworking.
I know PVC is preferable to MC in the case of feeders, subfeeds, and possibly home runs,
but I think they swap for branch.
-->

## Slab Thickness

Conduits may not be routed through slabs of thickness
less than 3 times the outer diameter of the conduit.

| Conduit Size | Minimum Slab Thickness (in) |
| ------------:| ---------------------------:|
|         1/2" |                         3.0 |
|         3/4" |                         3.5 |
|           1" |                         4.0 | 
|       1-1/4" |                         5.0 |
|       1-1/2" |                         6.0 |
|           2" |                         7.5 |
|           3" |                         9.0 |
|       2-1/2" |                        10.5 |
|       3-1/2" |                        12.0 |
|           4" |                        13.5 |
|           5" |                        17.0 |
|           6" |                        20.0 |

## By Finish

Cable type raceways (MC, NM, SE)
may only be used where they will be concealed from view.

Exception:
Temporary provisions for unfinished spaces (e.g. core and shell retail)

## By Construction Type

Nonmetallic-sheathed cables (NM/SER)
are not permissible in Non-Combustible (Type I, II) constructions.

See [[ibc-construction-types]] for more info.

## By Use-Case

### Multi-Circuit Homeruns

> [!quote] Art Baldwin (pp.)
> Multi-circuit MC is not cost-effective
> when considering the difficulty of rework.
> Use conduit, even EMT if necessary.

* Market Type = Assisted Living: MC-AP may be required.

## By Specification

> [!info] Example Specs Relevant to Wiring Methods Selection
> * 26XXXX - Raceway And Boxes For Electrical Systems
> * 26XXXX - Conduits For Electrical Systems
> * 26XXXX - Underground Ducts And Raceways For Electrical Systems
> 
> * 26XXXX - Low-Voltage Electrical Power Conductors And Cables
> 
> * 26XXXX - General Requirements For Electrical
> * 26XXXX - Common Work Results For Electrical

### Electrical Metallic Tubing (EMT)

Set-screw fittings may not be acceptable.

> [!info]
> EMT has a third coupling type "indenter",
> which are crimped onto the conduit using a special tool.
> These are usually only mentioned in specifications
> to say that they are unacceptable.

> [!info] Edge Case: Vanderbilt Central Neighborhood Residential College
>
> > [!cite] Vanderbilt Central Neighborhood Residential College - Project Specifications (pp.)
> > Fittings for Type EMT Duct Raceways:
> > * Coupling Method: Compression coupling or Setscrew coupling.
> >   Setscrew couplings with only single screw per conduit are unacceptable.
>
> > [!quote] Joel Jansen via Microsoft Teams @ 2025-10-15 09:33 AM
> > use set screw 🙂

### Rigid Polyvinyl Chloride Conduit (PVC)

Not usually permissible exposed indoors in any construction,
except in Florida.

May require rigid stub-ups in certain cases,
which could make EMT more cost-effective.
Consult with the Senior Construction Estimator in this case.

## Flow Chart

```mermaid
flowchart LR
    A[Construction Type]
    A -- I, II --> B[Can can be run in slab?]
    B -- No --> D[Concealed?]
    B -- Yes --> PVC
    D -- No --> EMT
    D -- Yes --> MC
    A -- III, IV, V --> C[Concealed?]
    C -- No --> PVC
    C -- Yes --> NM/SER

```